Control mechanism for elements in well tools



June 18, 1957 c. E. REESBY ETAL 2,795,356

. CONTROL MECHANISM FOR ELEMENTS m WELL TOOLS Filed Nov. 25, 1955 Caf/Reesby -0r|// //e f3. 6777/? INVENTORS BY 7 .m advwa United StatesPatent CONTROL NIECHANISM FOR ELEMENTS IN WELL TOOLS Carl E. Reesby andOrville R. Smith, Houston, Tex., assignors to Halliburton Oil WellCementing Company, Harris County, Tex., a corporation of DelawareApplication November 25, 1955, Serial No. 549,058

7 Claims. (Cl. 33-178) This invention relates to tools used in wells andother earth bore holes and remote locations, and more particularly, to amechanism for the control of certain elements in such tools.

In many tools used in remote locations such as the bottoms of oil wells,it is necessary to obtain substantial forces for the control of certainelements in the mechanism of such tools. The problem is illustrated inthe caliper of Figure 1, wherein it is desired to hold the feelersretracted during descent into the well, then to release them forcalipering during some distance of upward movement of the caliper, andwherein it is sometimes desired to again retract the feelers and lowerthe tool again for a second calipering pass through a given section ofthe well, before pulling the tool up to the top of the well. When thetool is suspended perhaps two miles down in a well on a wire line,repeated control of the feelers, to the extent of locking them in aretracted position and releasing them for calipering, presents somedifficulties.

While some electrical energy may be transmitted to the tool in someuses, it is usually very difficult to transmit enough electric energy todirectly control such members as feelers, spring loaded arms, pads orpackers, in calipers, well logging and similar instruments, through afull cycle or more of operation and by conventional electric directcontrol means.

An object of this invention is to provide improved control means formovable members in tools used in remote locations such as oil wells.

A further object of this invention is to provide novel control means,wherein the energy of the fluids at the remote location is utilized fordesired control purposes.

Still another object is to provide an improved and novel caliper whereinthe feelers thereof may be released for calipering and thence retractedagain through a plurality of half-cycles, while the caliper remainspositioned in a well.

Other objects are apparent from the following description andaccompanying drawing.

These objects are accomplished in accordance with this invention, by theuse of a hydraulic system, including a high pressure chamber containinghydraulic fluid in communication with a low pressure chamber, at leastpartially filled with compressible gas. The high pressure chamber is inpressure communication with the fluid pressures external of the subjecttool or instrument, whereas the low pressure chamber is initially atrelatively low pressure such as atmospheric pressure. Fluid flowing fromthe high pressure to the low pressure chamber moves with the energyderived from the difierence between the pressure external of the tool inthe well and that in the low pressure chamber. A motor responsive to themovement of hydraulic liquid from one chamber to the other, is adaptedto control the retractable or other movable member of interest in theinstrument.

Figure 1 is an illustration of a typical caliper embodying theinvention.

Figure 2 is a schematic view of the hydraulic system used in the caliperof Figure 1, and usable in other tools ice to control retractablemembers through more than onehalf cycle.

Figure 3 is a schematic view of another embodiment of the hydraulicsystem of the invention.

In order that the problem solved by this invention may be fullyunderstood, reference may be made to the caliper of Figure l.

The caliper body 1 is depended from a logging line 2. The logging line 2includes both such electrical conductors as are required for theoperation of the caliper electrical elements and for recordation of thedata from the caliper, as indicated hereinafter.

Near the lower end of the caliper, a plurality of bell crank levers 4are pivotally mounted on the caliper body 1 by pins 5. Each bell cranklever lies in a plane radial from the caliper body, with the shorter endextending generally inward, and the longer end extending generallydownward and protruding outward from the caliper for engagement with thewall of the well. Accordingly, the outer end of each bell crank leverbecomes a feeler.

Each feeler is urged outward by the action of a tension coil spring 7mounted in the caliper to act upon a stem 8 which in turn urges theshort end of the bell crank lever downward.

At one end each stem 8 carries a rack 10, which cooperates with a pinion11. The pinion 11 controls a potentiometer which is immediately behindthe pinion 11, and therefore does not appear in Figure 1. The positionof the feeler controls the setting of the potentiometer, and a signalderived from the potentiometer is indicative of the position of thefeeler. The potentiometers are energized from the logging line 2 and thesignals derived from the various potentiometers are, either together orseparately as may be desired for the particular caliper operation,transmitted to the top of the well through the logging line 2.

If the caliper is to be lowered into the well, the caliper fingers mustbe held retracted. When the tool is positioned as low in the well asdesired, the fingers must be released, and then the calipering runcommenced. If a calipering run is made for, say 200 feet, and it isdesired for some reason to re-run the same 200 feet, the feelers must beretracted again for the 200 foot descent, then released again for the200 foot calipering run. If no further calipering is desired, it ispreferable to again retract the feelers for the run back to the surfaceof the ground, which may be as much as two miles or more in deep wells.

In the caliper illustrated, the feelers as a group are held retractedduring descent into the hole, by a collar 13, adapted to engage all ofthe inside ends of the bell crank arms 4 on the lower side. The collar13 is mounted on a rod 14. When the rod 14 is held upward, the collar 13controls the feelers, locking them inward, but when the rod 14 andcollar 13 are moved downward, the feelers extend outward freely fortheir calipering function.

The mechanism for controlling the reciprocating rod 14, and therebycontrolling the retractable feelers, is more easily understood by firstreferring to the hydraulic system detailed schematically in Figure 2.

In the hydraulic system of Figure 2, there are three cylinders, 15, 16and 17. Preferably, the first cylinder 15 is of substantially smallervolume than the second and third cylinders 16 and 17.

The rod 14 appears both in Figure l and Figure 2, and protrudes axiallyinto the cylinder 15. On the end of the rod 14 within the cylinder 15,there is a first piston 20 which divides the cylinder 15 into twochambers, a first chamber 21 and a second chamber 22.

Within the cylinder 16, there is a second piston 25 which divides thecylinder 16 into an anterior chamber 26. and a posterior chamber 27.Conveniently there may' be a valve 28 which when open, connects theposterior chamber to atmosphere. The valve 28 is closed during theoperation of the device, but may be used to relieve any pressure whichmay accumulate in the chamber 27 before disassembly of the tool forrepairs, or to remove any hydraulic fluid that may seep by the piston25. Within the posterior chamber 27, there may be a compression spring29 adapted to urge the piston 25 toward the anterior chamber 26.

Within the third cylinder 17, there is a third piston 31 which, inco-operation with a portion of the cylinder 17, defines a third or highpressure chamber 32. The side of the piston 31 which is opposite thehigh pressure chamber 32 is to open to the pressure of fluids immediately surrounding the tool.

Conduit and valve means are provided for connecting the high pressurechamber 32 into communication with the first chamber 21 and forconnecting the second chamber 22 into connection with the anteriorchamber 26. Valve and conduit means also afford a connection from thehigh pressure chamber 32 to the second chamber 22, and from the firstchamber 21 to the anterior chamber 26.

Conveniently the valve in such means may be a fourport rotary valve 35,with the four ports positioned at 90 degree intervals around the valve.In the embodiment of Figure 2 (details of which are not shown in Figure1), one of said ports is connected to the first chamber 21 by a conduit36; a second port is connected to the high pressure chamber 32 by aconduit 37; a third port, diametrically opposite the first, is connectedto the second chamber 22 by a conduit 38; and the fourth port,diametrically opposite the second, is connected to the anterior chamber26 by a conduit 39.

The four-port valve 35 has 3 positions. In one position, none of theports are connected to each other, as when it is turned 45 from theposition illustrated in Figure 2. With this valve position, hydraulicfluid flow is prevented and therod 14 is thereby locked in the positionWhere it is when the valve 35 is, turned to this neutral or offposition. The other two positions of the valve 35 are the oneillustrated in Figure 2, and a position 90 counter-clockwise from thatof Figure 2.

A solenoid 40 operating in conjunction with a gear train 41 (see Figurel) operates the valve 35. The solenoid is controlled by surface switchesconnected by wires in the logging line to the solenoid 40.

The central portion of the housing 1 is a liquid filled chamber housingmost of the works of the tool. the top of the housing 1, the housingassumes the form of a cylinder. A piston 42 with an O ring is slidab'lypositioned therein. The upper side of the piston 42 is open, throughports 43, to the well fluids. Accordingly, the liquid below the piston42 is always maintained at the same pressure as the well fluids externalof the tool, and any exposure of the upper side of the piston 31 (Figure2) to the liquid filling the housing 1, is an exposure of the piston 31to the pressures of Well fluids.

The operation of this embodiment of the hydraulic system can now beunderstood. The valve 35 is rotated to connect first the second chamber22, then the first chamber 21 to the high pressure chamber 32,correspondingly connecting the anterior chamber 26 to the first chamber21 and to the second chamber 22 at alternate times. Thereby hydraulicfluid, preferably a substantially noncompressible liquid, which fillsthe various conduits, and the anterior, first, second and high pressurechambers, is moved by the action of the spring 29 out of the anteriorchamber 26 and into the high pressure chamber 32. The posterior chamberis occupied with low pressure gas and the valve 28 is closed.

Assume that when the piston 25 is farthest down in Figure 2, that thepiston 20 is farthest up in both Figure l and Figure 2. At this timeconduit 37 is connected to Near conduit 36 and conduit 38 is connectedto conduit 39 by the valve 35. The feelers 4 are then supported inretracted position by the upward position of the collar 137 The tool, inthe condition described, is lowered into the well, say 12,000 feet for anumber of calipering runs between 12,000 feet and 10,000 feet. At suchdepths, the amount of electrical power that can conveniently be conveyedto the tool is usually limited, but great power resides in the highpressure of the well fluids, which pressure is greatly above atmosphericpressure.

When the tool reaches 12,000 feet, the solenoid 40 is energized to turnthe valve 35 to the position wherein the high pressure chamber 32 isconnected via conduits 37 and 38 to the second chamber 22, and so thatthe first chamber 21 is connected via conduits 36 and 39 to the anteriorchamber 26. With the valve in this position, the well pressures actingon the top of the piston 31 create a pressure diflerential across thefirst piston 20. Hydraulic fluid from the high pressure chamber 32 isurged into the second chamber 22, moving the piston 20, rod 14 andcollar 13, downward, releasing the feelers 4. Hydraulic fluid in thefirst chamber 21 is discharged via conduits 36 and 39 into the anteriorchamber 26. The piston 25 is moved upward against the atmosphericpressure and light spring in the posterior chamber 27.

The tool is then pulled upward 200 feet ina calipering run, whereupon itis desired to again retract the feelers. Since the high pressure chamber32 and the anterior chamber 26 are both larger in volume than is theentirety of the cylinder 15, including both the first and secondchambers 21 and 22, the first half cycle of operations require movementof the pistons 31 and 25 of only one-eighth of their travel, forexample.

The solenoid 40 is used to rotate the valve 35 so that the high pressurechamber 32 is connected to the first chamber 21, and thesecond chamber22 is connected to the anterior chamber 26. Thereupon, the well fluidspush the piston 31 downward another one-eighth of its travel, therebyreturning the piston 20, rod 14 and collar 13 to the upward position,and retracting the feelers 4.

The tool is then lowered again down to the l2,000 foot level, and thecycle repeated. The feelers may be withdrawn and released as many timesas desired, until all the hydraulic fluid in the high pressure chamber32 has been moved out and the anterior chamber 26 has been filled.

It is preferred that before the hydraulic fluid in the high pressurechamber 17 is exhausted, the feelers are retracted. Thereupon, the valve35 is turned to the neutral or off position, preventing any fluid flow,so as to hold the feelers in the retracted position as the tool is drawnback to the surface of the ground.

When the tool reaches the surface, the valve 35 may be rotated throughits extreme positions 90 apart, and the spring 29 then moves the piston25 downward and causes the hydraulic fluid to return to the highpressure chamber 32. The valve 28 may be opened at this time if desired,though this is not normally necessary.

The hydraulic system has been defined with reference to the Figure 2embodiment, but other embodiments are equivalent. Consider, for example,the embodiment of Figure 3. Again there is the rod 14 and piston 20. Thepiston '20 is positioned in a cylinder so as to define therein twochambers which this time are designated and 46. At one side, the leftside in Figure 3, of the chambers 45 and 46, is a high pressure chamber47. The high pressure chamber 47 is defined in part by a flexiblediaphragm 48.

On another side of the chambers 45 and 46, the right side in Figure 3,there is a single large chamber divided into an anterior chamber 50 anda posterior chamber 51 by another flexible diaphram 52.

The high pressure chamber 47' is connectable by a valve 54 to the firstchamber 45, and by another valve 55 to greases connectable by a valve 56to the first chamber 45 and by another valve 57 to the second chamber46. The posterior chamber may be opened to the atmosphere by a valve 58.

If electrical means are provided for the operation of the various valves55, 56, 57 and 58, then the structure of Figure 3 may be operatedidentically with that of Figure 2. The rod 14 may be moved downward byopening valves 55 and 56, so that hydraulic fluid, urged by the flexiblediaphram 48 which is open to well pressures, is moved from the highpressure chamber 47 into the second chamber 46, and from the firstchamber 45 into the anterior chamber 50, causing the flexible diaphram52 to move against near atmospheric gas pressure in the posteriorchamber 51. The rod 14 may be moved upward by Opening valves 54 and 57,so that hydraulic fluid is moved from the high pressure chamber 47 intothe first chamber 45 and from the second chamber 46 into the anteriorchamber 50.

It is apparent that both the piston 31, of Figure 2, and the flexiblediaphram 48 of Figure 3, constitute means for communicating the fluidpressure external of said instrument to the hydraulic liquid in saidhigh pressure chamber. Conventional bellows could also be adapted forthis purpose.

The anterior and posterior chambers may be considered as one lowpressure chamber, and if desired, the dividing piston (Figure 2) ordiaphragm 52 (Figure 3) may be eliminated, without affecting theoperation of the device once it is set for lowering into the well withthe low pressure chamber substantially full of relatively low pressuregas. The piston 25 and diaphragm 52 are included merely for conveniencein resetting the device prior to each run in a well.

Speaking broadly, the cylinder which defines the first and secondchambers 21 and 22 (Figure 2) or 45 and 46 (Figure 3) is a motor whichis responsive to fluid flow in either of two directions to generatemechanical forces in either of two directions. Other hydraulic motors,i. e., fluid flow responsive means, may be used to convert the fluidflow into mechanicalmotion, although the cylinder piston arrangement hasbeen found to be most convenient for use in well tools.

Other embodiments of the invention will be apparent to those skilled inthe art. For example, it may be found convenient to arrange two, or evenall three, of the cylinders of Figure 2 concentrically. Accordingly, theforegoing description is to be construed as illustrative only and not asa limitation upon the invention as defined in the following claims.

We claim:

1. In an instrument adapted to be run in a well and having a retractablemember adapted to protrude therefrom, a hydraulic system for controllingsaid member comprising the combination of a first cylinder with a firstpiston therein which is responsive to hydraulic fluid pressuredifferentials on opposite sides thereof in either of the two alternativedirections, said piston being connected by a linkage to said controlledmember whereby said piston drives and controls said member in itsmovement from one of its positions to the other; a low pressure chamberin the form of a second cylinder, said cylinder being divided intoanterior and posterior chambers by a second piston movably mountedtherein, said posterior chamber containing gas at a pressure relativelylow in comparison with the pressure of well fluids and in volume greaterthan twice the volume of hydraulic fluid which said first cylinder canhold; a third piston slidably mounted in a third cylinder to define inco-operation with said third cylinder at high pressure chambercontaining hydraulic fluid in a volume greater than twice the volume ofsaid first cylinder, said third piston having one side thereof exposedto the pressures of Well fluids whereby said high pressure chamber ismaintained at pressures equal to that of the well fluids; a valve withfour ports and a movable elementadapted either to connect the first portto the second and the third port to the fourth, or alternatively toconnect the, first port to the fourth and the second to the third;conduits connecting said high pressure chamber to said first port, oneend of said first cylinder to said second port, the other end of saidfirst cylinder to said fourth port, and said anterior chamber to saidthird port, whereby said valve and conduits may, convey the pressurediflFerential between said high pressure and low pressure chambers toopposite sides of said first piston in alternative directions toactivate said piston to movement in alternative directions; and a meansfor operating said valve to efiect either of said alternative pressuredifferential applications.

2. In an instrument adapted to be run in a well and having a retractablemember therein, a hydraulic system for controlling said membercomprising the combination of a hydraulic motor including a cylinderwith a piston therein which is responsive to hydraulic fluid pressurediiferentials in either of two alternative directions, said piston beingconnected by a linkage to said controlled member whereby said motordrives and controls said member in its movement from one of itspositions to the other; a low pressure chamber divided by a movableelement therein into anterior and posterior, chambers, said posteriorchamber containing gas at a pressure relatively low in comparison withthe pressure of well fluids and in volume greater than twice the volumeof hydraulic fluid which said cylinder can hold; a high pressure chambersubstantially filled with hydraulic fluid; means for communicating thepressure of said well fluids to the hydraulic fluid in said highpressure chamber; a valve having conduit means for connecting said highpressure chamber and said low pressure chamber to said motor in eitherof two alternative manners, so that a pressure differential may becreated in said motor in either of two alternative directions and causesaid motor to move in either of two alternative directions; and a meansfor operating said valve means to effect connections in either of twoalternative manners.

3. The invention defined in claim 2 wherein said valve and conduit meanscomprise a valve with four ports and a movable element adapted either toconnect the first port to the second and the third port to the fourth,or alternatively to connect the first port to the fourth and the secondto the third; a conduit connecting said high pressure chamber to saidfirst port; a conduit connecting one end of said cylinder to said secondport; a conduit connecting the other end of said cylinder to said fourthport; and a conduit connecting said third port to said anterior chamber.

4. In an instrument adapted to be run in a well and having a controlledmember therein which is to be moved to either of two alternativepositions during the operation of the instrument, a hydraulic system forcontrolling said controlled member comprising the combination of ahydraulic motor with a moving element responsive to hydraulic fluidpressure difierentials in either of two alternative directions, saidmoving element being connected by a linkage to said controlled memberwhereby said motor drives and controls said member in its movement fromone of its positions to the other; a low pressure chamber containing asubstantial quantity of gas at a pressure relatively low in comparisonwith the pressure of well fluids; a high pressure chamber containinghydraulic fluid; means for communicating the pressure of said wellfluids to the hydraulic fluid in said high pressure chamber; a valvehaving conduit means for connecting said high pressure chamber and saidlow pressure chamber to said motor in either of two alternative manners,whereby a pressure dilferential may be created in said motor in eitherof two alternative directions and cause said motor to move in either oftwo alternative directions; and a means for operating said valve meansto effect connections in either of two alternative manners.

5. In an instrument adapted to be operated in a high fluid pressureenvironment upon remote actuation and having a controlled member thereinwhich is to be moved to either of .two alternative positions during theoperation of the instrument, a hydraulic system for controlling saidcontrolled member comprising the combination of a hydraulic motor with amoving element responsive to hydraulic fluid pressure differentials ineither of two alternative directions, said moving element beingconnected by a linkage to said controlled member whereby said motordrives and controls said member in its movement from one of itspositions to the other; a low pressure chamber containing a substantialquantity of gas at a pressure relatively low in comparison with thefluid pressure of the environment surrounding said instrument; a highpressure chamber containing hydraulic fluid; means for communicating thefluid pressure of said environment to the hydraulic fluid in said highpressure chamber; a valve having conduit means for connecting said highpressure chamber and said low pressure chamber to said motor in eitherof two alternative manners, so that a pressure differential may beapplied to said motor in either of two alternative directions and causethe moving element in said motor to move in either of two alternativedirections; and a means responsive to actuation externally of saidenvironment for operating said valve means to eflect connections in eachof said two alternative manners.

6. In an instrument adapted to be run in a well and having a retractablemember therein, means for controlling said retractable member comprisingthe combination of a high pressure chamber containing hydraulic liquid;means for communicating the fluid pressure external of said instrumentto the hydraulic liquid in said high pressure chamber; a low pressurechamber containing fluid including a substantial quantity of gas atnormally much lower pressure than the pressure in said well external ofsaid instrument; a motor responsive to liquid flow to produce mechanicalpower in either of two alternative directions, depending upon thedirection of liquid flow through said motor; said motor beingconnectable through a valve and conduit means to said high pressurechamber and said low pressure chamber in either of two alternative ways,so that liquid may flow from the high pressure chamber to the lowpressure chamber, passing through the motor in either of two alternativedirections in response to the pressure differential between said twochambers; and a linkage connecting said motor to said retractable memberwhereby said retractable member is controlled by said motor.

7. In an instrument adapted to be run in a well and having a retractablemember adapted to protrude therefrom, the combination of a firstcylinder and first piston assembly wherein said first piston ispositioned slidably within said first cylinder to define first andsecond chambers; a second cylinder and second piston assembly whereinsaid second piston is positioned slidably within said second cylinder soas to define an anterior chamber and a posterior chamber within saidcylinder; at third cylinder and third piston assembly wherein said thirdpiston is positioned slidably within said third cylinder, wherein saidthird piston has one side thereof exposed to the pressures of wellfluids external of the instrument and wherein the second side of saidpiston co-operates with said first cylinder to define a third chamber;said second and third cylinders being each of volume at least twice thatof said first cylinder; a valve having conduit means for connecting saidthird chamber into communication with said first chamber and said secondchamber into communication with said anterior chamber, and foralternatively connecting said third chamber into communication with saidsecond chamber and said first chamber into communication with saidanterior chamber; means for activating said valve means to change fromeach of said alternate connections to the other of said alternativeconnections; and a linkage connecting said retractable member to saidfirst piston, whereby said retractable member is moved in response tothe movement of said first piston.

References Cited in the file of this patent UNITED STATES PATENTS1,290,203 Honk Jan. 7, 191.9 2,290,479 Mercier July 21, 1942 2,622,334Wiley Dec. 23, 1952 2,640,275 Boucher June 2, 1953

